What is matrix reasoning?

Matrix Reasoning is a type of visual-spatial problem solving that is often used to determine intelligence. It usually involves a series of figures in which there is a discernible pattern, with one figure in the series left blank. The problem is solved by determining, from an array of possibilities, what figure would complete the series or pattern. Here is a good example: http://psycnet.apa.org/journals/law/2/3-...